Unless you get lucky, most restorations require a little metalwork eventually. Some panels require heavy repairs, such as rust and serious collision damage while others just need a little massaging. The latter type of repair is what brings us here today. There are many ways to repair minor body damage like minor door dings, creases and dents. For doors, quarter panels and other large panels, body hammers and fillers are a better choice, but for removable panels such as fenders, hoods, and trunks lend themselves to working with an english wheel and planishing hammer. This is an age-old technique that, as of late, enjoyed resurgence in popularity realm of custom hot rod and motorcycle building, but its roots go back to the early days of the automobile when coach builders made each body by hand. The English wheel is one of those tools.
An English wheel is a simple device that employs a large fixed-position steel wheel to press sheet metal over a smaller rolling die. The radius of the smaller die determines the size of the curve induced on the metal. This particular process is not only useful for manipulating flat metal, it lends itself perfectly to smoothing out dents, dings and creases in existing forms. By matching radius of the rolling die, the defect can easily be rolled out, reducing and in some cases, eliminating the need for body filler. The English wheel is considered a rough forming tool, generally, the part requires some smoothing, typically performed with a planishing hammer.
While the English wheel is a hand-operated device, the planishing hammer requires air-power to operate. This device uses an air-hammer to drive a wide, flat anvil up and down onto the sheet metal. As with the english wheel, the lower tool die is what determines the amount of curve. The tool dies are mounted onto a stationary post and the metal glides over the die. As the anvil comes down, the metal is bent over the die, adding shape. The speed of the anvil is controlled by a foot pedal, and the power of the strike is controlled at the hammer itself. The planishing hammer can perform both forming and finishing shaping. For complex compound curves and shapes, I prefer to use the planishing hammer as it works the metal faster and maneuverability is much better.
During the metal shaping process, the metal becomes work hardened as the molecules of the metal are squeezed closer together. Eventually, the metal gets too difficult to work and progress grinds to a halt. While not a really a big problem in dent repair, it surely is a problem with patch panels. There is a trick that will “loosen” the metal back up so work can continue. It is called annealing and is quite simple. Basically, an acetylene torch is set up with sooty flame (no oxygen) and the metal is slowly heated up, being careful not to overheat the metal. All you need is for it to get hot, not glowing. The metal is left to cool and then the soot is cleaned off. This process allows the molecules in the metal to spread apart, allowing the process to start over. While not necessary, annealing can be done at the beginning, before even starting the process. This helps when the metal is heavy, such as 16 ga.
To demonstrate this process, we took a rear fender off a 1947 Plymouth business coupe that had spent a long portion of its life running up and down gravel roads. The result was fenders riddled with rock dings that come from the inside. Along with that, there were a few creases that ran right down the heavily crowned top portion of the fender. Since the fenders come off, the English wheel and planishing hammer should make quick work of the fender, smoothing the fender, and leaving a panel that should only require a skim coat of filler.